package com.hmdp.service.impl;

import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import cn.hutool.json.JSONUtil;
import com.alibaba.fastjson.JSON;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.entity.RedisData;
import com.hmdp.entity.Shop;
import com.hmdp.mapper.ShopMapper;
import com.hmdp.service.IShopService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.CacheClient;
import com.hmdp.utils.RedisConstants;
import com.hmdp.utils.SystemConstants;
import org.apache.commons.lang3.StringUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.geo.Distance;
import org.springframework.data.geo.GeoResult;
import org.springframework.data.geo.GeoResults;
import org.springframework.data.redis.connection.RedisGeoCommands;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.domain.geo.GeoReference;
import org.springframework.stereotype.Service;

import java.time.LocalDateTime;
import java.util.*;
import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

import static com.hmdp.utils.RedisConstants.*;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class ShopServiceImpl extends ServiceImpl<ShopMapper, Shop> implements IShopService {


    @Autowired
    private StringRedisTemplate stringRedisTemplate;

    @Autowired
    CacheClient cacheClient ;

    @Override
    public Result querybyId(Long id) {
        String shopId = CACHE_SHOP_KEY+id;

        //这里采用的是JSON转化的

        //从redis查询缓存
//        String shopJson = stringRedisTemplate.opsForValue().get(shopId);
//
//        //isnotblank这个方法包括不是空串 和Null串
//        if(StringUtils.isNotBlank(shopJson)){
//            Shop shop= JSON.parseObject(shopJson,Shop.class);
//            return Result.ok(shop);
//        }

        //不是null串但是空串 下面是错误写法
//        if(shopJson.isEmpty()){
//            return Result.ok("别访问了，没有你要找的值");
//        }
//        if(shopJson!=null){
//            return Result.ok("别访问了，没有你要找的值");
//        }
//
//        //如果没查到就从数据库里调用
//        Shop shop= getById(id);
//
//        //空值过期日期就是设置短一点
//        if(shop==null){
//            stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY+id,"",CACHE_NULL_TTL, TimeUnit.MINUTES);
//            //返回错误信息
//            return Result.fail("店铺不存在");
//        }
//        //缓存空串，解决缓存穿透的问题
//        stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY+id,JSON.toJSONString(shop),30L, TimeUnit.MINUTES);
//
//        return Result.ok(shop);

        Shop shop = cacheClient.queryWithMutex(shopId,id,Shop.class,this::getById,10L,TimeUnit.MINUTES);
        if (shop==null){
            return Result.ok("你要访问的店铺不存在");
        }

        return Result.ok(shop);
    }


    @Override
    public Result updateShop(Shop shop) {
        Long id = shop.getId();

        if(id==null){
            return Result.fail("商户id不能为空");

        }

        updateById(shop);

        //先操作数据库尽可能的避免双写问题
        //如果先更新数据库  尽可能防止缓存和存储不一致
        stringRedisTemplate.delete(CACHE_SHOP_KEY+id);

        return Result.ok();

    }


    public Shop queryWithMutex(Long id)  {
        String key = CACHE_SHOP_KEY + id;
        // 1、从redis中查询商铺缓存
        String shopJson = stringRedisTemplate.opsForValue().get("key");
        // 2、判断是否存在
        if (StrUtil.isNotBlank(shopJson)) {
            // 存在,直接返回
            return JSONUtil.toBean(shopJson, Shop.class);
        }
        //判断命中的值是否是空值
        if (shopJson != null) {
            //返回一个错误信息
            return null;
        }
        // 4.实现缓存重构
        //4.1 获取互斥锁
        String lockKey = LOCK_SHOP_KEY + id;
        Shop shop = null;
        try {
            boolean isLock = tryLock(lockKey);
            // 4.2 判断否获取成功
            if(!isLock){
                //4.3 失败，则休眠重试
                Thread.sleep(50);
                return queryWithMutex(id);
            }
            //4.4 成功，根据id查询数据库
            //这里按照理解应该有一个新的线程
            shop = getById(id);
            // 5.不存在，返回错误
            if(shop == null){
                //将空值写入redis  缓存穿透
                stringRedisTemplate.opsForValue().set(key,"",CACHE_NULL_TTL,TimeUnit.MINUTES);
                //返回错误信息
                return null;
            }
            //6.写入redis
            stringRedisTemplate.opsForValue().set(key, JSON.toJSONString(shop),CACHE_NULL_TTL,TimeUnit.MINUTES);

        }catch (Exception e){
            throw new RuntimeException(e);
        }
        finally {
            //7.释放互斥锁
            unlock(lockKey);
        }
        return shop;
    }
    private boolean tryLock(String key) {
        Boolean flag = stringRedisTemplate.opsForValue().setIfAbsent(key, "1", 10, TimeUnit.SECONDS);
        return BooleanUtil.isTrue(flag);
    }

    private void unlock(String key) {
        stringRedisTemplate.delete(key);
    }

    //定义一个线程池
    private static  final ExecutorService executor = Executors.newFixedThreadPool(10);


    //暂时就不考虑缓存击穿的问题了
    public Shop queryWithlogicExpire(Long id){
        String key = CACHE_SHOP_KEY+id;


        String shopJson = stringRedisTemplate.opsForValue().get(key);

        if (StringUtils.isBlank(shopJson)){
            return  null;
        }

        RedisData redisData = JSON.parseObject(shopJson,RedisData.class);

        Shop shop = (Shop) redisData.getData();

        LocalDateTime localDateTime = redisData.getExpireTime();

        if(localDateTime.isAfter(LocalDateTime.now())){
            return  shop;
        }

        //已经过期,重建缓存

        //新建一个runnable的任务

        Runnable runnable =new Runnable() {
            @Override
            public void run() {
                saveShopRedis(id,20L);
            }
        };

        Runnable runnable1 = () -> {

            };


        String lockkey  = LOCK_SHOP_KEY+id;
        boolean islock = tryLock(lockkey);

        if (islock){
            executor.submit(runnable);

        }


        //记住这里很重要，新建一个线程重建缓存，将旧数据直接返回了
        return shop;


    }

    private void saveShopRedis(Long id, long l) {

        Shop shop = getById(id);

        RedisData redisData =new RedisData();

        redisData.setData(shop);
//        if(shop == null){
//            //将空值写入redis  缓存穿透
//            stringRedisTemplate.opsForValue().set(key,"",CACHE_NULL_TTL,TimeUnit.MINUTES);
//            //返回错误信息
//        }
//        //6.写入redis
//        stringRedisTemplate.opsForValue().set(key, JSON.toJSONString(shop),CACHE_NULL_TTL,TimeUnit.MINUTES);
//
        redisData.setExpireTime(LocalDateTime.now().plusSeconds(l));

        stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY+id,JSON.toJSONString(redisData));

    }
    @Override
    public Result queryShopByType(Integer typeId, Integer current, Double x, Double y) {
        // 1.判断是否需要根据坐标查询
        if (x == null || y == null) {
            // 不需要坐标查询，按数据库查询
            Page<Shop> page = query()
                    .eq("type_id", typeId)
                    .page(new Page<>(current, SystemConstants.DEFAULT_PAGE_SIZE));
            // 返回数据
            return Result.ok(page.getRecords());
        }

        // 2.计算分页参数
        int from = (current - 1) * SystemConstants.DEFAULT_PAGE_SIZE;
        int end = current * SystemConstants.DEFAULT_PAGE_SIZE;

        // 3.查询redis、按照距离排序、分页。结果：shopId、distance
        String key = SHOP_GEO_KEY + typeId;
        GeoResults<RedisGeoCommands.GeoLocation<String>> results = stringRedisTemplate.opsForGeo() // GEOSEARCH key BYLONLAT x y BYRADIUS 10 WITHDISTANCE
                .search(
                        key,
                        GeoReference.fromCoordinate(x, y),
                        new Distance(5000),
                        RedisGeoCommands.GeoSearchCommandArgs.newGeoSearchArgs().includeDistance().limit(end)
                );
        // 4.解析出id
        if (results == null) {
            return Result.ok(Collections.emptyList());
        }
        List<GeoResult<RedisGeoCommands.GeoLocation<String>>> list = results.getContent();
        if (list.size() <= from) {
            // 没有下一页了，结束
            return Result.ok(Collections.emptyList());
        }
        // 4.1.截取 from ~ end的部分
        List<Long> ids = new ArrayList<>(list.size());
        Map<String, Distance> distanceMap = new HashMap<>(list.size());
        list.stream().skip(from).forEach(result -> {
            // 4.2.获取店铺id
            String shopIdStr = result.getContent().getName();
            ids.add(Long.valueOf(shopIdStr));
            // 4.3.获取距离
            Distance distance = result.getDistance();
            distanceMap.put(shopIdStr, distance);
        });
        // 5.根据id查询Shop
        String idStr = StrUtil.join(",", ids);
        List<Shop> shops = query().in("id", ids).last("ORDER BY FIELD(id," + idStr + ")").list();
        for (Shop shop : shops) {
            shop.setDistance(distanceMap.get(shop.getId().toString()).getValue());
        }
        // 6.返回
        return Result.ok(shops);
    }
}
